Which is entirely true - but since the amount of damage being caused to you is being compared with that which can occur through the typical combo mechanics, I think it’s relevant to look at all the differences/similarities.
If you’re opening me up for a combo, I could avoid it by not getting hit or blocking it - with Annhilation, the same applies - don’t get hit.
But, once I’ve been hit and I’m in a combo, the mind games begin and I have opportunities to break and reduce the amount of damage I’m taking, while the opponent needs to manage their KV and Shadow meters. You don’t have that opportunity whatsoever - one touch is guaranteed damage relative to how much Instinct meter he had left, there’s absolutely nothing you can do about it.
When you’re comparing Omen’s move and SJ’s Annihilation, you have a full life bar of potential damage versus up to 48% guaranteed, unbreakable damage for landing the attack, but again, Omen’s move can be defended against outside of avoiding being hit in the first place, and doesn’t have the benefit of a guaranteed Instinct Cancel into freeze when activating it like SJ’s does.
Are these similarities and differences really not worth discussing, and simply boiled down to simply “don’t get hit?”